LISLE, Ill. -- Tellabs Inc. posted fourth-quarter results Tuesday that were in line with Wall Street's expectations, but its shares tumbled after the telecommunications-products maker warned that first-quarter earnings will fall short of estimates.

Tellabs said it will likely earn 30 cents a share in the first quarter, compared with analysts' mean estimate of 33 cents a share. Tellabs shares were down $11.0625, or 16%, to $58 in...